feat(kebab-tui): p9-fb-24 task 1 — pager module + PAGE_STEP constant

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-tui/src/lib.rs

@@ -22,6 +22,7 @@ mod input;
 mod inspect;
 mod library;
 mod markdown;
+mod pager;
 mod run;
 mod search;
 mod terminal;

crates/kebab-tui/src/pager.rs

@@ -0,0 +1,11 @@
+//! p9-fb-24: page-step constant shared by Ask + Inspect PgUp/PgDn.
+//!
+//! Fixed `10` rows per page (independent of viewport height). The
+//! design doc considered viewport-aware paging but deliberately
+//! deferred it — Inspect already shipped with `+/-10`, so unifying
+//! on the same constant is the smallest path that closes the
+//! "Ask has no PgUp/PgDn" feedback. A future viewport-aware upgrade
+//! lives behind this single edit point.
+
+/// Rows scrolled per `PgUp` / `PgDn` keystroke.
+pub(crate) const PAGE_STEP: u16 = 10;